QUESTION 1 [TOTAL MARKS: 100] Q 1(a) [30 Marks] State the selection rule that a diatomic...

 

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QUESTION 1 [TOTAL MARKS: 100] Q 1(a) [30 Marks] State the selection rule that a diatomic molecule must comply with to be microwave active. With the aid of a diagram, briefly explain the physical basis of this selection rule. Q 1(b) HCI has a rigid rotor rotational constant of 10.44 cm-¹ (i) Calculate the most intense transition in the HCI pure rotational spectrum at 10 °C and at 300 °C. Determine the bond length of HCI. [40 Marks] Q 1(c) [30 Marks] For a theoretical rigid rotor molecule XY, draw an energy level diagram showing the first 6 rotational energy levels for this molecule. Your diagram should: €€ (1) Include expressions for the energy and rotational quantum numbers of each level. Indicate the allowed transitions between rotational states. Indicate, with a dashed line, what would happen to the relative energies of each state if one of the atoms was replaced with a heavier isotope. Include a brief explanation in your answer of the origin of such isotope effects. [End of Question 1] QUESTION 1 [TOTAL MARKS: 100] Q 1(a) [30 Marks] State the selection rule that a diatomic molecule must comply with to be microwave active. With the aid of a diagram, briefly explain the physical basis of this selection rule. Q 1(b) HCI has a rigid rotor rotational constant of 10.44 cm-¹ (i) Calculate the most intense transition in the HCI pure rotational spectrum at 10 °C and at 300 °C. Determine the bond length of HCI. [40 Marks] Q 1(c) [30 Marks] For a theoretical rigid rotor molecule XY, draw an energy level diagram showing the first 6 rotational energy levels for this molecule. Your diagram should: €€ (1) Include expressions for the energy and rotational quantum numbers of each level. Indicate the allowed transitions between rotational states. Indicate, with a dashed line, what would happen to the relative energies of each state if one of the atoms was replaced with a heavier isotope. Include a brief explanation in your answer of the origin of such isotope effects. [End of Question 1]

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a Solution Not 66 allowed selection Rotational So ... View the full answer